(go to KOMUGI Home) (go to WIS List) (go to NO.80 Contents)

2. Production of hexaploid x Trititrigia from E.elongata 4x.

The seed set in the crosses T.durum cv. Italy363 x tetraploid E.elongata was rather low (1.4%). Morphology of the F1 hybrids was intermediate between parents and the hybrids were perennial but self sterile. Chromosome pairing in the F1 hybrids averaged 13.8I+ 6.9II+ 0.2 III. BC1 seed set on the F1 hybrids using Italy363, Kekereiter and Yenminmai pollen was low (11.2%). Chromosome number was 42 in root tip cells of the BC1F1 plants and the chromosome pairing averaged 7.5I+ 17.1II+ 0. 1III. The BC1F1 plants had a low self fertility (29.6%). One BC1F1 plant showed a high self fertility (71 %). All of the BC1F2 plants derived from the self-fertilized BC1F1 plant had 2n=40-42. The derivatives obtained in the process of successive self-fertilization showed normal fertility and a high incidence of bivalents in meiosis. The BC1F1 plants in our study were apparently derived from the fusion of an unreduced gamete of the F1 hybrid with a normal gamete of T.durum. Charpentier, Cauderon, Feldman (1988) proposed E1E1E2E2 as the genomic constitution for tetraploid Elytrigia elongata. The genomic constitution of the F1 hybrids thus was ABE1E2 and that of the BC1F1 plants was AABBE1E2. The genomes of AABB might play a role as a pivotal genome in these plants. Its derivatives would be AABBE1E1 or AABBE2E2. These are, therefore, partial amphiploid, hexaploid x Trititrigia (Fig. 2).

3. Morphology and agronomic characteristics of hexaploid x Trititrigia.

The hexaploid x Trititrigia lines had shorter spike internodes, larger spikelets than E.intermedia and tetraploid E.elongata. The hexaploid x Trititrigia from E.intermedia had an erect growth habit. The line of 8704-1-89 survived for three years and exhibited strong heterosis, vigorous tillering, and flowering lasted for several weeks. The line of 363-1-21 showed strong resistance to powdery mildew. The hexaploid x Trititrigia from tetraploid E.elongata lacked an erect growth habit and had similar growth habit to Chinese Spring. During flowering, they had yellow and purple anthers. Their seeds showed a color similar to tetraploid E.elongata. The hexaploid x Trititrigia from E.intermedia and E.elongata 4x showed strong resistance to rust, barley yellow dwarf virus and good quality. They expressed high crossability with common wheat and octoploid x Trititrigia. The plant height, number of ears per plant, spikelet length, awn length and other agronomic characteristics are shown in Table 1.

<--Back | -->Next

(go to KOMUGI Home) (go to WIS List) (go to NO.80 Contents)